A facile procedure for the preparation of saturated and ulisaturated L-a-lecithins from L-a-glycerylphosphorylcholine (GPC) is reported. The lecithins are obtained by acylating I.-a-GPC, in the form of its cadmium chloride addition compound, with fatty acjd chloride and pyritline a t low temperature (0°-2.5'). The acylation proceeds rap~dly and yields optically pure L-a-lecithins. The preparation of the tlistex-oyl-, dimyristoyl-, and dioleoyl L-a-lecithi 11s by this procedure is described.The deacylatioil of lecithins with mercuric chloride or sodium hydroxide was investigated. Both procedures give a partially racemized L-a-GPC. This was established by the finding that the optical activity of the lecithins resulting from reacylating the L-a-GPC preparations in the form of their cadmium chloride compountls was considerably lower than that of the corresponding authentic lecithins.Can. J. Biochem. Physiol. Downloaded from www.nrcresearchpress.com by University of Otago on 07/29/15For personal use only.

The stereochemical course of the hydrolysis of synthetic sn‐glycerol‐1‐palmitate‐2‐oleate‐3‐linoleate, sn‐glycerol‐1,2‐dipalmitate‐3‐oleate and their antipodes by pancreatic and milk lipoprotein lipase was investigated by thin layer and gas liquid chromatographies of the diacylglycerol intermediates. The enzymic hydrolyses were made with bile salts or lysolecithin in a 1∶1 molar ratio to the substrate as emulsifiers and were limited to short time intervals which minimized isomerization and the reversal of lipolysis. In all instances, the products of hydrolysis by lipoprotein lipase contained a marked preponderance of the 2,3‐diacylglycerols, while the composition of the diacylglycerol intermediates in the products of pancreatic lipase varied with the nature of the fatty acid in the 1 and 3 positions of the triacylglycerol molecule. Pancreatic lipase, but not lipoprotein lipase, gave a preferential release of unsaturated fatty acids. The above results are similar to those obtained with radioactive trioleoylglycerol and conventional stereospecific analyses and suggest that lipoprotein lipase may favor attack on the sn‐1 position. It is hypothesized that the small amounts of the 1,2‐diacylglycerols present may have arisen from a reversal of lipolysis also catalyzed by this enzyme.

Chromatography on silicic acid‐boric acid columns permits detritylation of ester lipids, essentially without acyl migration, and simultaneous separation of the reaction products. Described is the preparation of the column and its application for the synthesis of diacyl‐sn‐glycerols and 2‐acyl‐1,2‐propaneiols.

Procedures have been developed for the synthesis of both enantiomeric forms of mixed fatty acid, saturated and polyunsaturated 1,2-diacyl-sn-glycerols and 2,3-diacyl-sn-glycerols from D-mannitol as starting material. The following diacyl-sn-glycerols have been synthesized: 1-Stearoyl-2-linoleoyl-sn-glycerol, 1-stearoyl-2-linolenoyl-sn-glycerol, 2-linoleoyl-3-stearoyl-sn-glycerol and 2-linolenoyl-3-oleoyl-sn-glycerol. Their specific rotations, refractive indices, densities, solubilities, carbon and hydrogen analysis and iodine values have been reported.

PERCENTAGR nF cis ISOMER PRODUCRD 4-Phenylmercaptocamphane (XI).-4-Campliyllithium was prepared following the procedure described by Winstein .' The 4-camphyllithium reagent in cyclohexane was filtered through the sintered glass funnel directly into a solution of cyclohexane containing 10 g. (7.2 g., 0.067 mole required) of phenyl disulfide. As the lithium reagent was added, the reactiou mixture turned milky white, but very little heat was evolved. After the addition was complete, the mixture was heated undcr reflux for 2 to 3 hours. The reaction mixture was then cooled and added slowly t o a solution of 5 g. of lithium aluminum hydride in ethyl ctlicr t o reduce the excess phenyl disulfide t o thiophenol. After the reduction was complete, the excess hydride was destroyed with ethyl acetate, and the solution was poured slowly into excess 6 N sulfuric acid solution containing much chopped ice. After separation of the organic layer, the water layer was extracted twice with cyclohexane. The combined organic layers were then extracted five times with equal volumes of 570 sodium hydroxide solution, washrd with water, and dried over anhydrous potassium carbonate. The solvent was removed at atmospheric pressure through a column, and the residue was heated gently in a subliming tube under reduced pressure (15 mm.). Unreactcd 4-chlorocamphane, 2.75 g. (24% recovery), sublimed onto the walls of the tube and was carefully removed. The yellow residual oil was then distilled under reduced pressure. On redistillation, 10.2 g. (62%) of 4-phenylmercaptocamphane was obtained as a colorlcss oil, which could not be induced t o crystallize, b.p. 110--12l0 (0.1 mm.), n% 1.5567.